Temperature control device for motor vehicle, for example electrical or hybrid

ABSTRACT

The temperature regulation device ( 10 ) comprises a heat pump ( 12 ) having a main refrigerant fluid circuit ( 14 ) taking heat from a cold source ( 16 ) and transferring it to a hot source ( 18 ), the cold source ( 16 ) including a refrigerant fluid/air heat exchanger ( 26 ) designated as first evaporator. The cold source ( 16 ) also comprises a refrigerant fluid/coolant liquid heat exchanger ( 28 ) designated as second evaporator ( 28 ), thermally coupling the main refrigerant fluid circuit ( 14 ) to a secondary coolant liquid circuit ( 38 ) capable of being connected at least to a first secondary heat exchanger ( 42, 44 ) in heat exchange with a first heat source of the vehicle. The first and second evaporators ( 26, 28 ) being connected in parallel.

The present invention relates to a temperature regulation device for amotor vehicle, e.g. of the electrical or hybrid type.

A hybrid type vehicle combines two sources of energy for propulsionpurposes: an electric motor and a heat engine. In an electrical orhybrid type vehicle, the electric motor is powered by a battery andcontrolled by an electronic power device.

Proper operation of the battery depends on the temperature of the airsurrounding the battery, and in particular on ambient temperatureoutside the vehicle. In general, the battery is deactivated when itstemperature exceeds a maximum value of about 55° C. However batterylifetime can be increased by further restricting its maximumtemperature, for example to avoid said maximum temperature exceeding 35°C., as much as possible.

It is known that the battery can be cooled by means for causing a flowof air to circulate in contact with the battery. As a general rule, thebattery cooling air comes from the vehicle cabin. The means for airconditioning the cabin thus contribute to cooling the battery. In avariant, the battery cooling air can come from outside the vehicle.

Thus, in the state of the art, a temperature regulation device isalready known for a motor vehicle, the device being of the typecomprising a heat pump having a main refrigerant fluid circuit takingheat from a cold source and transferring it to a hot source, the coldsource including a refrigerant fluid/air heat exchanger designated asfirst evaporator.

The evaporator is conventionally constituted by a refrigerant fluid/airheat exchanger arranged in the cabin for cooling the air of the cabin.Air taken from the cabin serves to cool the battery.

As with the battery, it is also appropriate to limit the temperature ofthe electronic power device.

It is known to cool the electronic power device by means of a coolantliquid circuit (generally a mixture of water and antifreeze) connectedto a coolant liquid and air heat exchanger arranged in the front face ofthe vehicle. At the outlet from the heat exchanger, the temperature ofthe coolant liquid is generally lowered to about 60° C. Nevertheless,the volume and the cost of the electronic power device could be reducedby further reducing the temperature of the coolant liquid for coolingsaid device, e.g. down to 20° C.

The invention seeks in particular to optimize firstly operation andlifetime of the battery and secondly bulk and cost of the electronicpower device, while modifying as little as possible the configuration ofthe engine compartment and of the means for air conditioning the vehiclecabin.

To this end, the invention provides a motor vehicle temperatureregulation device of the above-specified type, characterized in that thecold source also comprises a refrigerant fluid/coolant liquid heatexchanger designated as second evaporator, thermally coupling the mainrefrigerant fluid circuit to a secondary coolant liquid circuit capableof being connected at least to a first secondary heat exchanger in heatexchange with a first heat source of the vehicle, the first and secondevaporators being connected in parallel.

According to characteristics of various embodiments of the device:

-   -   the second secondary coolant liquid circuit is suitable for        being connected to a second secondary heat exchanger in heat        exchange with a second heat source of the vehicle;    -   the first and second secondary heat exchangers are connected in        parallel in the secondary coolant liquid circuit;    -   the main refrigerant fluid circuit comprises first and second        parallel evaporator branches connected respectively to the first        and second evaporators, each evaporator branch including a        respective expansion valve disposed downstream or upstream from        the evaporator;    -   the first evaporator branch includes a valve for regulating the        fluid flow rate and preferably disposed downstream from the        first evaporator;    -   the expansion valve and the regulation valve in the first        evaporator branch constitute a single member;    -   the secondary cooling liquid circuit is provided with a pump for        driving said cooling liquid;    -   the hot source includes a refrigerant fluid/air heat exchanger        designated as condenser, preferably disposed in the engine        compartment of the vehicle;    -   the first evaporator of the cold source is disposed in a cabin        of the vehicle;    -   the second evaporator of the cold source is disposed in a        portion of the vehicle that is distinct from the cabin;    -   each secondary heat exchanger is disposed in a portion of the        vehicle that is distinct from the cabin;    -   each hot source is selected from an exothermal member of the        vehicle, such as a member forming an electronic power device, a        power supply battery for an electrical vehicle drive motor, or a        fuel cell, and the air for supercharging a heat engine of the        vehicle;    -   the refrigerant fluid of the main circuit is of the R134a type;    -   the refrigerant fluid of the main circuit comprises carbon        dioxide;    -   the main circuit includes an intermediate heat exchanger having        passing therethrough both a branch of the main circuit upstream        from the compressor and a branch of the main circuit downstream        from the condenser; and    -   the coolant liquid of the secondary coolant liquid circuit is a        mixture of water and antifreeze.

The invention will be better understood on reading the followingdescription given purely by way of example and made with reference tothe accompanying drawings, in which:

FIGS. 1 and 2 are block diagrams of a temperature regulation deviceconstituting two respective embodiments of the invention; and

FIGS. 3 to 5 are diagrammatic views of a temperature regulation deviceconstituting three respective other embodiments.

FIG. 1 shows a temperature regulation device for a motor vehicle, inparticular of the electrical or hybrid type, constituting a firstembodiment of the invention. This temperature regulation device isdesignated by overall reference 10.

In the text below, two members are said to be thermally coupled togetherwhen they exchange heat between each other by means of a suitable heatexchanger.

The temperature regulation device 10 comprises a heat pump 12 comprisinga main compression type refrigerant fluid circuit 14 taking heat from acold source 16 and transferring at least some of to it to a hot source18.

The cold and hot sources 16 and 18 are connected to each other by acompressor 20 (electrical or mechanical). The refrigerant fluidvaporizes, taking heat from the cold source 16. The compressor 20 sucksin the vaporized fluid and delivers it towards the hot source 18 whereit condenses while cooling down. The refrigerant fluid flow direction inthe main circuit 14 is shown by arrows in FIG. 1. The refrigerant fluidflowing in the main circuit 14 is of conventional type. The refrigerantfluid is selected, for example, from a chlorine and fluorine-containingderivatives of methane or ethane (Freon), a hydrocarbon, ahydrofluorocarbon (HFC), ammonia, etc.

In the example described, the refrigerant fluid is R134a (HFC).

By way of example, the hot source 18 comprises a refrigerant fluid/airheat exchanger 24 designated as condenser.

The compressor 20 and the condenser 24 are arranged in a compartment C1of the vehicle that preferably constitutes the engine compartment of thevehicle. By way of example, the condenser 24 is arranged in a front faceof the vehicle.

The cold source 16 comprises a refrigerant fluid/air heat exchanger 26designated as first evaporator, and a refrigerant fluid/coolant liquidheat exchanger 28 designated as second evaporator.

These first and second evaporators 26 and 28 are connected respectivelyto first and second parallel evaporator branches 30 and 32 of the mainrefrigerant fluid circuit 14. The first and second evaporators 26 and 28are thus connected in parallel.

Each evaporator branch includes a respective expansion valve 34, 36 (acalibrated orifice thermostatic or electronic valve) disposed downstreamfrom the evaporators 26, 28, as shown in FIG. 1, or upstream from theevaporators 26, 28. Each expansion valve 34, 36 allows the refrigerantfluid to pass towards the corresponding evaporator 26, 28 by loweringits pressure.

The first evaporator branch 30 includes a fluid flow regulation valve,in particular of the on/off type, preferably disposed downstream fromthe first evaporator 26. In the example shown, this regulation valve andthe expansion valve of the first branch 30 are constituted by a singlemember 34.

The second evaporator 28 thermally couples the main refrigerant fluidcircuit 14 to a secondary coolant liquid circuit 38. The circuit 38includes a pump 40, preferably an electrical pump, for circulating thecoolant liquid, and connected in the example shown to an output of thesecond evaporator 28. In a variant, the pump 40 could be disposedupstream from the second evaporator 28.

The coolant liquid of the secondary circuit 38 is, for example, amixture of water and antifreeze.

The direction in which the coolant liquid circulates in the secondarycircuit 38 is shown by arrows in FIG. 1.

The secondary circuit 38 may be connected firstly to a first secondaryheat exchanger 42 in heat exchange with a first exothermal member of thevehicle, and secondly to a second secondary heat exchanger 44 in heatexchange with a second exothermal member of the vehicle.

The first and second secondary heat exchangers 42 and 44 are connectedin parallel in the secondary coolant liquid circuit 38. It should beobserved that the branch of the secondary circuit 38 to which the secondsecondary heat exchanger 44 is connected includes a valve 46 forregulating the flow of the coolant liquid, in particular an on/off typevalve, preferably disposed downstream from said secondary heat exchanger44.

In the example described, the first exothermal member in heat exchangewith the heat exchanger 42 is constituted by an electronic power devicefor controlling an electric motor for driving the vehicle. In addition,the second exothermal member in heat exchange with the heat exchanger 44is constituted by a power supply battery for the electric motor of thevehicle.

In a variant, the secondary coolant liquid circuit 38 could be connectedto a single secondary heat exchanger, for example the heat exchanger 44in heat exchange with the battery.

It should be observed that in the invention the exothermal members inheat exchange with the heat exchangers 42 and 44 could be any exothermalmembers.

The first evaporator 26 is disposed, for example, in a compartment C2 ofthe vehicle constituting a vehicle cabin, and more particularly a cabinair conditioner unit. The second evaporator 28 and the two secondaryheat exchangers 42 and 44 are disposed, for example, in a compartment C3of the vehicle that is distinct from the cabin. By way of example, thecompartment C3 may be formed by the engine compartment (in which casethe compartments C1 and C2 are identical, or by a compartment disposedbeneath the floor of the vehicle cabin).

The main aspects of the operation of the temperature regulation device10 of the invention are described below.

a) Operation of the Temperature Regulation Device 10 in Cold Conditions

When the vehicle is started, the exothermal members in heat exchangewith the heat exchangers 42 and 44 do not need to be cooled since theirtemperature is sufficiently low. Similarly, the vehicle cabin has noneed to be cooled.

As a result, the heat pump 12 and the pump 40 of the secondary coolantliquid circuit 38 are deactivated.

After the electric motor of the vehicle has been operated for a certainlength of time, the temperature of the exothermal members in heatexchange with the heat exchangers 42, 44 rises. The heat pump 12 and thepump 40 of the secondary circuit 38 are then activated. The valve 46enables the cooling of the exothermal member associated with the secondsecondary heat exchanger 44 to be adjusted in accordance withrequirements. The compressor 20 operates at a low rate that issufficient for removing heat coming from the exothermal members and thesecondary circuit 38 to the hot source 18 of the heat pump.

The valve 34 enables cooling of the cabin to be adjusted in accordancewith requirements.

Where appropriate, the compressor 20 operates at a faster rate in orderto enable the cabin to be cooled via the first evaporator 26 that isdisposed in said cabin.

b) Operation of the Temperature Regulation Device 10 in Hot Conditions

Under such circumstances, the compressor 20 generally operates at a highrate so as to cool firstly the cabin via the first evaporator 26 andsecondly the exothermal members via the second evaporator 28.

If during operation of the vehicle it is no longer necessary to cool theexothermal members, the pump 40 is deactivated.

FIG. 2 shows a temperature regulation device constituting a secondembodiment of the invention. In FIG. 2, elements that are analogous tothose of FIG. 1 are designated by references that are identical.

In this second embodiment of the invention, shown in FIG. 2, therefrigerant fluid of the main circuit 14 comprises carbon dioxide.

The main circuit 14 includes a conventional intermediate heat exchanger48 with a branch of the main circuit 14 upstream from the compressor 20and a branch of the main circuit 14 downstream from the condenser 24passing therethrough.

Amongst the advantages of the invention, it should be observed that thesecondary coolant liquid circuit 38 coupled to the heat exchanger 12 bythe second evaporator 28 enables the battery and the electronic powerdevice of an electrical or hybrid vehicle to be cooled effectively. As aresult, the maximum temperature of the battery can be restricted so asto increase the lifetime of the battery. Furthermore, the temperature ofthe coolant liquid in heat exchange with the electronic power device canbe lowered effectively compared with a conventional temperatureregulation device so as to enable the volume of said electronic deviceto be significantly reduced.

Under hot conditions, the secondary coolant liquid circuit 38 thermallycoupled to the cold source 16 of the heat pump enables the temperatureof the battery to be cooled quickly so as to stabilize it at a value ofabout 35°, thereby guaranteeing a relatively long lifetime for thebattery.

The reaction time of the batteries on a hot start can be reduced.

The invention thus makes it easier to use electrical or hybrid vehiclesin hot regions.

Finally, the invention can be fitted to existing vehicles withoutsignificantly altering the configuration of the engine compartment andof the means for air conditioning the cabin of such a vehicle.

FIGS. 3 to 5 show temperature regulation devices constituting third tofifth embodiments of the invention, respectively. In these figures,elements analogous to those of the preceding figures are designated byreferences that are identical.

In FIG. 3, the cold and hot sources 16 and 18 are interconnected by thecompressor 20 and an expansion valve 122. The refrigerant fluidcirculating in the main circuit 14 is of a conventional type. Thisrefrigerant fluid is selected, for example, from a chlorine- andfluorine-containing derivative of methane or ethane (Freon), ahydrocarbon, ammonia, carbon dioxide, etc.

The compressor 20, the expansion valve 122, and the condenser 24 aredisposed in a compartment C1 of the vehicle.

The second evaporator 28 thermally couples the main refrigerant fluidcircuit 14 to a secondary coolant liquid circuit 130. This circuit 130includes a pump 132, preferably an electrical pump, for circulating thecoolant liquid, and connected in the example shown to an output of thesecond evaporator 28. In a variant, the pump 132 could be disposedupstream from the second evaporator 28.

By way of example, the coolant liquid of the secondary circuit 130 is amixture of water and antifreeze.

The secondary circuit 130 can be connected firstly to a first secondaryheat exchanger 134 in heat exchange with a first exothermal member ofthe vehicle, and secondly to a second secondary heat exchanger 136 inheat exchange with a second exothermal member of the vehicle.

The first and second secondary heat exchangers 134 and 136 are connectedin parallel in the cooling liquid secondary circuit 130.

In the example described, the first exothermal member in heat exchangewith the heat exchanger 134 is constituted by an electronic power devicefor controlling an electric motor that drives the vehicle. Furthermore,the second exothermal member in heat exchange with the heat exchanger136 is formed by a battery for powering the electric motor of thevehicle.

In a variant, the cooling liquid secondary circuit 130 could beconnected to a single secondary heat exchanger, e.g. the heat exchanger136 in heat exchange with the battery.

It should be observed that in the invention the exothermal members inheat exchange with the heat exchangers 134 and 136 may be any exothermalmembers.

The cooling liquid secondary circuit 130 includes a valve 138 providedwith a first port 138A connected to the output of the second evaporator28, via the pump 132, a second port 138B connected to an input of thefirst secondary heat exchanger 134, and a third port 138C connected toan input of the second secondary heat exchanger 136.

The first and second evaporators 26 and 28 are connected in series.These evaporators 26 and 28 may be integrated in a common module or elsethey may be separate from each other.

In the third embodiment shown in FIG. 3, the second evaporator 28 isdisposed downstream from the first evaporator 26 in the refrigerantfluid circulation direction in the main circuit 14.

Furthermore, it should be observed in this third embodiment that thefirst evaporator 26 and the second evaporator 28 are arranged in thecompartment C2. However, both secondary heat exchangers 134 and 136 aredisposed in the compartment C3 of the vehicle that is distinct from itscabin.

The main aspects of operation of the third embodiment of the temperatureregulation device 10 are described below.

c) Operation of the Temperature Regulation Device 10 in Cold Conditions

On starting the vehicle, the exothermal members in the exchange with theheat exchangers 134, 136 do not need to be cooled since theirtemperature is low enough. Similarly, the vehicle cabin does not need tobe cooled.

As a result, the heat pump 12 and the pump 132 of the coolant liquidsecondary circuit 130 are deactivated.

After the electric motor of the vehicle has been operating for a certainlength of time, the temperature of the exothermal members in heatexchange with the heat exchangers 134, 136 rises. The heat pump 12 andthe pump 132 of the secondary circuit 130 are then activated. The valve138 is adjusted in such a manner as to enable each exothermal member tobe cooled in accordance with its requirements. The compressor 20operates at a low rate that is sufficient for extracting the heat thatcomes from the exothermal members and from the secondary circuit 130 viathe hot source 18 of the heat pump.

Where necessary, the compressor 20 operates at a faster rate so as toenable the cabin to be cooled via a first evaporator 26 disposed in thecabin.

d) Operation of the Temperature Regulation Device 10 in Hot Conditions

Under such circumstances, the compressor 20 generally operates at a highrate so as to cool firstly the cabin via the first evaporator 26 andsecondly the exothermal members via the second evaporator 28.

If during operation of the vehicle it is no longer necessary to cool theexothermal members, the pump 132 is deactivated.

In the fourth embodiment, as shown in FIG. 4, the second evaporator 28is disposed upstream from the first evaporator 26 so as to optimize thecooling of the exothermal members in the exchange with the heatexchangers 134, 136.

In the fifth embodiment, shown in FIG. 5, the second evaporator 28 isdisposed in the compartment C3 that is distinct from the cabin, formingan engine compartment or a compartment disposed beneath a cabin floor ofthe vehicle.

Placing the second evaporator 28 in the engine compartment makes iteasier to integrate the temperature regulation device 10 of theinvention in a conventional vehicle by avoiding any need to modifysignificantly the configuration of the already-existing means for airconditioning the vehicle cabin.

Naturally, a combination of the various embodiments of the invention asdescribed above is possible without going beyond the ambit of theinvention.

Amongst the advantages of the invention, it should be observed that thesecondary coolant liquid circuit 103 coupled to the heat pump 12 by thesecond evaporator 28 enables the battery and the electronic power deviceof an electrical or hybrid vehicle to be cooled effectively. As aresult, the maximum temperature of the battery can be restricted to 45°C., thereby enabling battery lifetime to be increased, in particular byone-third compared with the normal lifetime. Furthermore, thetemperature of the coolant liquid in heat exchange with the electronicpower device can be lowered by about 40° C. compared with a conventionaltemperature regulation device, thus enabling the volume of saidelectronic power device to be reduced by about 1 liter.

In hot conditions, the secondary coolant liquid circuit 130 thermallycoupled to the cold source 16 of the heat pump enables the temperatureof the battery to be reduced quickly so as to stabilize it to the valueof about 45° C., thereby guaranteeing a relatively long lifetime for thebattery.

The invention is not limited to the embodiments described above. Inparticular, each secondary heat exchanger may be in heat exchange withany heat source of the vehicle, for example a fuel cell, or a heatsource other than an exothermal member, for example air forsupercharging a vehicle engine.

Under such circumstances, the engine is generally supercharged by meansof a turbocompressor unit provided firstly with a turbine driven by theexhaust gases of the engine and disposed downstream from the engine, andsecondly by an air admission compressor disposed upstream from theengine. The air admitted to the engine is heated in the compressor andcan be cooled on leaving the compressor by a secondary heat exchanger ofthe device of the invention so as to optimize the performance of theengine and minimize the emission of pollution.

1-16. (canceled)
 17. A temperature regulation device of a motor vehicle,the device comprising a heat pump including a main refrigerant fluidcircuit comprising a main refrigerant fluid that transfers heat from acold source to a hot source, the cold source comprising a firstevaporator connected in parallel to a second evaporator, the firstevaporator adapted to exchange heat between refrigerant fluid and air,the second evaporator adapted to exchange heat between refrigerant fluidand a coolant liquid, the main refrigerant fluid circuit thermallycoupled to a secondary coolant liquid circuit capable of being connectedto at least one secondary heat exchanger adapted to exchange heat withat least one heat source of the vehicle.
 18. The device of claim 17,wherein the device includes a plurality of secondary cooling liquidcircuits connected to respective heat sources.
 19. The device of claim18, wherein the secondary heat exchangers are connected in parallel. 20.The device of claim 17, wherein the main refrigerant fluid circuitcomprises first and second parallel evaporator branches connectedrespectively to the first and second evaporators, each evaporator branchincluding an expansion valve.
 21. The device of claim 20, wherein thefirst evaporator branch includes a regulator valve for regulating fluidflow rate.
 22. The device of claim 21, wherein the main refrigerantfluid in the main refrigerant fluid circuit flows from an upstreamposition to a downstream position, and the valve is disposed downstreamfrom the first evaporator.
 23. The device of claim 21, wherein a singlemember comprises the expansion valve and the regulator valve.
 24. Thedevice of claim 17, wherein the secondary cooling liquid circuitincludes a circulation pump for moving the cooling liquid.
 25. Thedevice of claim 17, wherein the hot source includes a condenserincluding a refrigerant fluid/air heat exchanger.
 26. The device ofclaim 25, wherein the condenser is disposed in an engine compartment ofthe vehicle.
 27. The device of claim 17, wherein the first evaporator isdisposed in a cabin of the vehicle.
 28. The device according to claim17, wherein the second evaporator is disposed in a portion of thevehicle that is distinct from a cabin of the vehicle.
 29. The device ofclaim 18, wherein each secondary heat exchanger is disposed in a portionof the vehicle that is distinct from a cabin of the vehicle.
 30. Thedevice of claim 17, wherein the hot source comprises an exothermalmember of the vehicle.
 31. The device of claim 30, wherein theexothermal member is selected from the group consisting of an electronicpower device, a power supply battery for an electrical vehicle drivemotor, a fuel cell, and the air for supercharging a heat engine of thevehicle.
 32. The device of claim 17, wherein the refrigerant fluid ofthe main circuit comprises R134a type fluid.
 33. The device of claim 17,wherein the refrigerant fluid of the main circuit comprises carbondioxide.
 34. The device of claim 33, wherein the main refrigerant fluidflows from an upstream position through a compressor to a downstreamposition through a condenser, and the main circuit includes anintermediate heat exchanger passing both an upstream branch of the maincircuit upstream from the compressor and a downstream branch of the maincircuit downstream from the condenser.
 35. The device of claim 1,wherein the secondary coolant liquid circuit includes a coolant liquidcomprising water and antifreeze.